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Read speed 37.5 MB/s, write 35.6. This seems to be a very common problem. Is there no solution? I haven't installed any vendor hardware. I also have a Samsung T5 which is equally slow.
iMac 21.5″, macOS 12.5
peterdanckwerts wrote:
Sorry, I should have said. It's an M1 iMac, so no USB 2.
That does not matter, you can still get only a USB2 connection if a cable, adapter, dock, hub, or enclosure only supports USB2 transfers or may be defective.
FYI, one great example is the Apple USB-C charging cable which only allows for USB2 rated transfers.
It's USB 3.1 and I've tried several Apple-certified cables.
What is USB 3.1? And which exact Apple certified cables did you try? Like I said Apple sells USB-C cables which are only rated for USB2 speeds which are considered charging cables by Apple. If you want a USB3+ rated USB-C cable from Apple, then you need to get the much more expensive Apple cable rated for USB3 & Thunderbolt 3 like this one here:
https://www.apple.com/shop/product/MQ4H2AM/A/thunderbolt-3-usb%E2%80%91c-cable-08-m
There are similar stories of these slow speeds on Apple Silicon, especially with Samsung SSDs, all over the internet.
I've seen them here on the forums too, but the majority of times it is due to using the wrong cable, adapter, dock, hub, or enclosure. Or maybe there is a hardware issue with the computer or the drive. Those transfer speeds are almost certainly showing the drive is connected as a USB2 device (some numbers scream things like this so this is where you should first begin the investigation by performing the checks I mentioned in my previous post).
Another suggestion is to reboot the Mac as well in case the Mac and macOS has gotten into some weird state, but I am fairly certain it is due to some cable, adapter, dock, hub, enclosure issue....or another connected device is interfering with this SSD. I can certainly be wrong, but this is something very easy to check to confirm by looking at the Apple System Profiler USB section and seeing what type of connection you have and its transfer speeds.
peterdanckwerts wrote:
Sorry, I should have said. It's an M1 iMac, so no USB 2.
That does not matter, you can still get only a USB2 connection if a cable, adapter, dock, hub, or enclosure only supports USB2 transfers or may be defective.
FYI, one great example is the Apple USB-C charging cable which only allows for USB2 rated transfers.
It's USB 3.1 and I've tried several Apple-certified cables.
What is USB 3.1? And which exact Apple certified cables did you try? Like I said Apple sells USB-C cables which are only rated for USB2 speeds which are considered charging cables by Apple. If you want a USB3+ rated USB-C cable from Apple, then you need to get the much more expensive Apple cable rated for USB3 & Thunderbolt 3 like this one here:
https://www.apple.com/shop/product/MQ4H2AM/A/thunderbolt-3-usb%E2%80%91c-cable-08-m
There are similar stories of these slow speeds on Apple Silicon, especially with Samsung SSDs, all over the internet.
I've seen them here on the forums too, but the majority of times it is due to using the wrong cable, adapter, dock, hub, or enclosure. Or maybe there is a hardware issue with the computer or the drive. Those transfer speeds are almost certainly showing the drive is connected as a USB2 device (some numbers scream things like this so this is where you should first begin the investigation by performing the checks I mentioned in my previous post).
Another suggestion is to reboot the Mac as well in case the Mac and macOS has gotten into some weird state, but I am fairly certain it is due to some cable, adapter, dock, hub, enclosure issue....or another connected device is interfering with this SSD. I can certainly be wrong, but this is something very easy to check to confirm by looking at the Apple System Profiler USB section and seeing what type of connection you have and its transfer speeds.
Seems like the SSD is connecting as a USB2 device since that is the limit of of USB2 transfers. You can confirm this by checking the Apple System Profiler USB section to see the connection type & speed of the connection. To access the System Profiler, Option-click the Apple menu & select the top item.
Try connecting the SSD directly to the Mac. Try using another USB cable.
Try disconnecting all other external devices in case one of them is causing a problem.
What is the exact model of this Mac? Only Macs from 2012+ have USB 3 ports....any older Mac only has at most a USB2 port where transfers are maxed at between 35MB/s - 50MB/s. You can get the exact model of the Mac by clicking the Apple menu and selecting "About This Mac".
Sorry, I should have said. It's an M1 iMac, so no USB 2. It's USB 3.1 and I've tried several Apple-certified cables. There are similar stories of these slow speeds on Apple Silicon, especially with Samsung SSDs, all over the internet.
Are you connecting the drive directly or through a hub?
No. I was at one point but, when I realised how slow it was, I didn't – and it's just as slow now.
Excruciatingly slow Samsung T7 SSD on iMac running Ventura (13.4.1)
